Method of pelleting carbon black

ABSTRACT

A method of pelleting particulate solids employing a pelleter having separate upper and lower jackets by means of which the upper and lower sections of the pelleter can be maintained at different operating temperatures. In one embodiment of the invention, the wall of the pelleter which comprises the inner wall of the jackets is adapted with apertures through which that material introduced into the jacket to heat the wall of the pelleter is brought into contact with the material adhering to the inner wall of the pelleter to remove the adhering material therefrom.

United States Patent [191 Dollinger [451 Sept. 9, 1975 [54] METHOD OF PELLETING CARBON BLACK [75] Inventor: Robert E. Dollinger, Hurst, Tex.

[73] Assignee: Phillips Petroleum Company,

Bartlesville, Okla. [22] Filed: Oct. 9, 1973 [21] Appl. No.: 404,636

Related US. Application Data [63] Continuation-impart of Ser. No. 248,312, April 27,

1972, Pat. No. 3,779,683.

[52] US. Cl. 264/117; 23/314; 425/222 [51] Int. Cl. C09c 1/58 [58] Field of Search 264/117, 327, 169; 23/313,

23/314; 259/DIG. l8, DIG. 22;

[56] References Cited UNITED STATES PATENTS 3,186,928 6/1965 Keaton ct a1. 264/117 Walenciak 264/1 17 3,459,844 8/1969 Cole 264/1 17 3,493,350 2/1970 Howard 23/314 3,528,785 9/1970 Dingus 264/117 Primary Examiner-Robert F. White Assistant Examiner-T. E. Balhoff 57 ABSTRACT A method of pelleting particulate solids employing a pelleter having separate upper and lower jackets by means of which the upper and lower sections of the pelleter can be maintained. at different operating temperatures. In one embodiment of the invention, the wall of the pelleter which comprises the inner wall of the jackets is adapted with apertures through which that material introduced into the jacket to heat the wall of the pelleter is brought into contact with the material adhering to the inner wall of the pelleter to remove the adhering material therefrom.

5 Claims, 3 Drawing Figures METHOD OF PELLETING CARBON BLACK This is a continuation-in-part of application Ser. No. 248,312 filed Apr. 27, I972, now US. Pat. No. 3,779,683.

This invention relates to the pelleting of particulate.

solids.

In one of its more specific aspects this invention rclates to the pelleting of carbon black. I

The pelleting of particulate solids in pin-type pellet ers is well known. For example, the pelleting of carbon black is disclosed in US. Pat. No. 3,607,086. Generally, pelleting isdone in a horizontally-positioned chamber adapted with mixing means. usually a horizontally disposed pinned shaft, and conduit means for in troducing the particulate solid to be pelleted and a pelleting agent. During the pelleting process, the solid is contacted by the pins as the shaft rotates and the particles are conveyed from their point of entrance to the exit of the chamber during which timethe particles are agglomerated into pellets.

Among those materials employed in pelleting can be various pelleting agents, usually liquids, which facilitate the pelleting of the solids. Inasmuch as the pins on the rotating shaft almost contact the inner surface of the pelleter, the action of the pins tends to establish a thin layer of solids on the inner wall of the pelleter. This layer retards the rotation of the shaft, causes pin wear, and increases power requirements to rotate the shaft. The method of this invention is directed towardsthc solution of this problem.

According to this invention, method of pelleting particulate solids is provided in which a particulate solid is agitated within a walled chamber, the pelleter, in the presence of a liquid to pellet the solid and to cause a portion of the solid to adhere with the pelleting liquid to the inner wall of the chamber. At least oneliquid or gaseous fluid is introduced into at least one jacket contacting the outer wall of a portion of the chamber. to vaporize at least a portion of the liquid contained in the solids adhering to the corresponding inner wall of thcchamber andto heat the adhering solids. This heating is believed to remove some of the liquid from the adhering solids and to cause the solids to shrink. This shrinkage, in turn, causes the adhered solids to be removed from the corresponding inner wall of the chamber. The solids are recovered as pellets from the pelleter. I j

By removing the adhering layer of particulate solids from the wall of the pelleter, pin wear is reduced and power requirements to rotate the shaft are decreased.

In one embodiment .of this invention, the lower sec tion of the pelleter of the upper section of the pelleter is heated.

In another embodiment of this invention, both the upper and lower sections are heated to like, or different temperatures. as desired. Either the upper section or the lower section can be heated to the higher temperature.

In another embodiment of this invention, that fluid introduced into the jackets adjacent either the upper or lower section of the pelleter is passed through aper turcs in the wall or walls of the pelleting chamber and into contact with the layer of solids adhering to the inner wall of the pelleter, under constant or pulsating pressure, to remove at least a portion of the solids from the wall.

.In the preferred embodime nt' of theinvention the lower section of the pelleter is heated to an elevated temperature by the introduetionof a high-temperature with the solids adhering =tothe rower ihhe'r wail of the pelleternA fluid at a lower'temp'erature is introduced into that jacket in association with the upper section of.

the pelleteryThis fluid is not, 'howevenpassed through apertures into the uppersection of the pelleter.

The method of :this invention is applicable to all pelletable solids and pelleting'age'nts, pelleters, and p'elleting procedures. It is particularly suited for the pelleting of-carbon blackand will bef'discussed hereinafter as applied thereto without intending to limit the' invention to that process, i

Any suitable fluid can be introducedinto the jackets and, optionally, through the apertures ofthe pelleter wall. Such fluids include s'teain, air, nitrogen and flue gas which can be employed at any desired temperature, elevated temperatures being attained by preheating. Preferably, a hot liquid is employed when only heating of the pelleter-wall is required and agaseous fluid is employed when the fluid is passed through apertures in the wall into contact with the adhering solids.

This invention will be more easily understood by referring to the attached drawing in which; i i

FIG. l is a view in elevation of apparatus suitable for employment in the invention and in which;

FIG. 2 is a cross-sectional view ofrthe apparatus in which the wall of the pelleter is not apertured;

FIG. 3 is a cross-sectional view of one embodiment in which both walls of the pelleter are 'apertured.

Referring now to FIGS. 1 and 2 there is shown pel- 5 on which a multiplicity of pins 6 are positioned, only a portion of the pins being shown for simplicity. The.

shaft is rotated by conventional drive means 7. For the introduction of pelleting agents, any number of conduits means 9, which can enter the chamber at any desired location, are provided. The chamber comp rises an upper section 10 and a lower section 11 which can be adapted for flanging by means of flanges l2 as shown in FIGS. 2 and 3.

Positioned around the outer periphery of sections 10 and 11 are separate upper and lower heat exchange zones, orjaekets, l3 and 13 into which a fluid or fluids are introduced through conduit means 14 and 14, the

fluids being removed from the jacket through conduits l5 and 15', respectively. Upon introduction of a hot fluid into the jackets, the inner surfaces 20 and 20' of sections 10 and 11 are heated with the result that the wet black cake which is adhered thereto becomes heated. As a result, vapor is produced from at least a portion of the liquid which is present in the cake, and the cake tends to shrink and be dislodged from the wall.

FIG. 3 is another embodiment of the invention having apertures I6 and I6 in the wall of the chamber. Apertures 16 can be positioned in wall 20 surrounding the upper zone 10 of the chamber and apertures 16' can be positioned in wall 20' surrounding lower zone 11, although only a single set of apertures can be employed. In this embodiment the fluid charged to the annularheat exchange zones 13 and 13 can enter the chamber 2 via apertures 16 and 16' to dislodge the cake from the inner periphery of the wall.

The following examples illustrate the method of the invention.

ln-both examples, the pelleter chamber is 24 inches in diameter and .9 feet in length and a conventional aqueous solution containing 1 weight percent molasses is employed. 1

In Example I, apertures are provided in the lower wall of the pelleter. These apertures are about l/32 inches in diameter, the total area of the apertures being about 0.01 sq. foot. Example I illustrates the preferred embodiment of the invention.

In Example II, no apertures are provided in either the upper or the lower section of the pelleter wall. Preheated air is introduced into both the upper and lower jackets at different temperatures to maintain a temperature differential of about 30F between the upper and lower sections of the pelleter.

Example I Feed to Pelleter: Carbon Black. No./hr. 3000 Carbon Black Temp.. "F 250 Pelleting Solution. No./hr. 3000 Pelleting Solution Temp.. "F lXS Pelleter Pressure Atmospheric Air to Top Jacket: Rate. No./hr. I000 Inlet Temperature. F 205 Outlet Temperature, "F 209 Inlet Pressure. psig l Steam to Lower Jacket: Rate, No./hr. 500* Inlet Temperature. F I 230 Outlet Temperature. "F 220 Pulsations/minutc Each Pulse On l.5 seconds Off 0.5 seconds Pelleter Shaft Speed. RPM 300 Wet Pellet Production. No,/hr. 6000 Pellet Temperature. "F 197 Cake Removed. No./hr.. est. 50

About 50 NtL/hr. pass through apertures.

' Example I] Feed .to Pelleter: Carbon Black. No./hr. 3000 Carbon Black'Temp. "F 250 Pelleting Solution. No./hr. 3000 Pelleting Solution Temp.. F I85 Pelleter Pressure Atmospheric Air to Top Jacket: Rate. No./hr. I000 Inlet Temperature. F 200 Outlet Temperature. "F 204 Inlet Pressure. psig. 5 Air to Bottom Jacket: Rate. No./hr. I000 Inlet Temperature. "F 230 Outlet Temperature. F 220 Inlet Pressure. psig. I5

Pclleter Shaft Speed. RPM Wet Pellet Production. No./hr. Pellet Temperature. F I Cake Removal. No./hr.. est.

From the above it will be seen that if the bottom zone of the pelleter is maintained above the boiling point of the pelleting liquid and the top zone is maintained less than the boiling point of the pelleting liquid, the adhering cake can be removed. Usually the lower portion of the pelleter will be maintained about 5 to 30TF above the boiling point of the pelleting liquid and the upper portion of the pelleter will be maintained about 5 to 10 below the boiling point of the pelleting liquid althoughany desired differential temperature can be employed.

It will be evident from the foregoing that various modifications can be made to the method of this invention. Such are considered, however, to be within the scope of the invention.

What is claimed is:

l. A method for forming pellets from a particulate solid comprising the steps of:

A. agitating said particulate solid within a walled chamber having an upper portion and a lower portion in the presence of a pelleting liquid whereby there are formed pellets of said solid and a layer consisting ofa mixture of pelleting liquid and solids adhering to theinner walls of the lower portion of said chamber;

B. contacting the lower portion of said walled chamber with a gaseous fluid having a temperature sufficient to heat said lower portion to a temperature above the temperature of the upper portion;

C. passing a portion of said gaseous fluid through the inner wall of at least said lower portion of said walled chamber and into the interior thereof so as to bring said gaseous fluid into contact with at least a portion of said pelleting liquid in said layer of pelleting liquid and solids so as to vaporize at least a portion of said liquid so as to thereby cause said layer to be removed from the lower portion of said walled chamber; and thereafter i g D. recovering the pellets of said particulate solid from'said chamber.

2. A process according to claim 1 wherein said particulate solid is carbon black.

3. A process according to claim 2 wherein said pelleting liquid is an aqueous molasses solution.

4. A process according to claim 2 wherein said gaseous fluid is pulsatingly introduced through said wall.

5. A process according to claim 2 wherein said gaseous fluid is air. 

1. A METHOD FOR FORMING PETTELS FROM A PARTICULATE SOLID COMPRISING THE STEPS OF: A. AGITATING SAID PARTICULATE SOLID WITHIN A WALLED CHAMBER HAVING AN UPPER PORTION AND A LOWER PORTION IN THE PRESENCE OF A PELLETTING LIQUID WHEREBY THERE ARE FORMED PELLETS OF SAID SOLID AND A LAYER CONSISTING OF A MIXTURE OF PELLETING LIQUID AND SOLIDS ADHERING TO THE INNER WALLS OF THE LOWER PORTION OF SAID CHAMBER, B, CONTACTING THE LOWER PORTION OF SAID WALLED CHAMBER WITH A GASEOUS FLUID HAVING A TEMPERATURE SUFFICIENT TO HEAT SAID LOWER PORTION TO A TEMPERATURE ABOVE THE TEMPERATURE OF THE UPPER PORTION, C. PASSING A PORTION OF SAID GASEOUS FLUID THROUGH THE INNER WALL OF AT LEAST SAID LOWER PORTION OF SAID WALLED CHAMBER AND INTO THE INTERIOR THEREOF SO AS TO BRING SAID GASEOUS FLUID INTO CONTACT WITH AT LEAST A PORTION OF SAID PELLETING LIQUID IN SAID LAYER OF PELLETING LIQUID AND SOLIDS SO AS TO VAPORIZE AT LEAST A PORTION OF SAID LIQUID SO AS TO THEREBY CAUSE SAID LAYER TO BE REMOVED FROM THE LOWER PORTION OF SAID WALLED CHAMBER, AND THEREAFTER D. RECOVERING THE PALLETS OF SAID PARTICULATE SOLID FROM SAID CHAMBER.
 2. A process according to claim 1 wherein said particulate solid is carbon black.
 3. A process according to claim 2 wherein said pelleting liquid is an aqueous molasses solution.
 4. A process according to claim 2 wherein said gaseous fluid is pulsatingly introduced through said wall.
 5. A process according to claim 2 wherein said gaseous fluid is air. 